Controlled vocabularies and why they matter

Standardize your information and data

Controlled vocabularies

In this webinar, metadata librarian Erin Antognoli discusses controlled vocabularies and how they fit into the use of metadata. If you haven’t yet listened to our previous discussions on metadata, “Metadata and the data lifecycle,” and “Choosing metadata standards,” you may want to take a few minutes to catch up.

What is a controlled vocabulary?

A controlled vocabulary is a vehicle that helps standardize information and provides a consistent representation of data across records and collections. Controlled vocabularies are more than just preferred terms, although that’s a big part of it. In addition, a controlled vocabulary:

  • Ensures wording and spelling are consistent.
  • Places limits on content entry in a particular field.
  • Specifies formatting.
  • Enables integration with linked data.

By specifying what can go into a metadata field, a controlled vocabulary maximizes the effectiveness of the metadata schema. Consistent terminology also aids findability and interoperability with other collections. When organized into a hierarchy, controlled vocabularies define how information will be structured and communicated—this also helps users search for and find what they need.

Types of controlled vocabularies

Different types of controlled vocabularies help achieve organizational goals. Once you’ve selected a metadata schema, you’ll want to ensure that each field contains a unique set of values. It certainly doesn’t make sense to have similar information in multiple fields, nor does it make sense to have different ways of referring to the same information.

It pays to invest time in determining the type of controlled vocabulary that will work best for the collection, as well as the permitted terminology for each field. This will be driven by the needs of the users and the vision for how the collection will interact with others in the future.

In the webinar, Antognoli reviews types of controlled vocabularies in order of complexity, including:

  • Flat term lists
  • Authority files
  • Classification schemes
  • Hierarchical term lists
  • Thesauri
  • Ontologies

She discusses the differences among them, along with examples of how they can be used depending on what kinds of relationships among terms are needed. There are many publicly-available controlled vocabularies, and Antognoli advises that before selecting one, it’s important to define how much detail will be included in the metadata. She also stresses that you must have an overall metadata strategy in place before getting into the details of a controlled vocabulary.

Learn more about the use of controlled vocabularies to provide consistency and structure to metadata in this latest installment of our Metadata for mere mortals webinar series.